Bacon.VolumeButton.ShowDock C# (CSharp) Method

        private bool ShowDock(Gdk.Event evnt)
        {
            Adjustment adj = slider.Adjustment;
            int x, y, m, dx, dy, sx, sy, ystartoff;
            uint event_time;
            double v;

            if(previous_volume != (int)slider.Adjustment.Lower) {
                previous_volume = Volume;
            }

            if(evnt is Gdk.EventKey) {
                event_time = ((Gdk.EventKey)evnt).Time;
            } else if(evnt is Gdk.EventButton) {
                event_time = ((Gdk.EventButton)evnt).Time;
            } else if(evnt is Gdk.EventScroll) {
                event_time = ((Gdk.EventScroll)evnt).Time;
            } else {
                throw new ApplicationException("ShowDock expects EventKey, EventButton, or EventScroll");
            }

            if(classic) {
                dock.Realize();
            }

            dock.Screen = Screen;

            GdkWindow.GetOrigin(out x, out y);
            x += Allocation.X;

            v = Volume / (adj.Upper - adj.Lower);

            if(classic) {
                dock.Move(x + (Allocation.Width - dock.Allocation.Width) / 2, y - dock.Allocation.Height);
                dock.ShowAll();
                Relief = ReliefStyle.Normal;
                State = StateType.Active;
            } else {
                y += Allocation.Y;

                dock.Move(x, y - (SCALE_SIZE / 2));
                dock.ShowAll();

                dock.GdkWindow.GetOrigin(out dx, out dy);
                dy += dock.Allocation.Y;

                slider.GdkWindow.GetOrigin(out sx, out sy);
                sy += slider.Allocation.Y;
                ystartoff = sy - dy;

                timeout = true;

                x += (Allocation.Width - dock.Allocation.Width) / 2;
                y -= ystartoff;
                y -= slider.MinSliderSize / 2;
                m = slider.Allocation.Height - slider.MinSliderSize;
                y -= (int)(m * (1.0 - v));

                if(evnt is Gdk.EventButton) {
                    y += (int)((Gdk.EventButton)evnt).Y;
                } else if(evnt is Gdk.EventScroll) {
                    y += (int)((Gdk.EventScroll)evnt).Y;
                }

                dock.Move(x, y);
                slider.GdkWindow.GetOrigin(out sx, out sy);
            }

            bool base_result = !classic && evnt is Gdk.EventButton
                ? base.OnButtonPressEvent((Gdk.EventButton)evnt)
                : true;

            Gtk.Grab.Add(dock);

            if(Gdk.Pointer.Grab(dock.GdkWindow, true,
                Gdk.EventMask.ButtonPressMask |
                Gdk.EventMask.ButtonReleaseMask |
                Gdk.EventMask.PointerMotionMask, null, null, event_time) != Gdk.GrabStatus.Success) {
                Gtk.Grab.Remove(dock);
                dock.Hide();
                return false;
            }

            if(Gdk.Keyboard.Grab(dock.GdkWindow, true, event_time) != Gdk.GrabStatus.Success) {
                Display.PointerUngrab(event_time);
                Gtk.Grab.Remove(dock);
                dock.Hide();
                return false;
            }

            if(!classic && evnt is Gdk.EventButton) {
                dock.GrabFocus();

                Gdk.EventButton evnt_copy = (Gdk.EventButton)Gdk.EventHelper.Copy(evnt);
                m = slider.Allocation.Height - slider.MinSliderSize;
                UpdateEventButton(evnt_copy, slider.GdkWindow, slider.Allocation.Width / 2,
                    ((1.0 - v) * m) + slider.MinSliderSize / 2);
                slider.ProcessEvent(evnt_copy);
                Gdk.EventHelper.Free(evnt_copy);
            } else {
                slider.GrabFocus();
            }

            pop_time = event_time;

            return base_result;
        }